Microsoft also says that Yammer added "a record 290 new paying customers" in the fourth quarter, including GlaxoSmithKline, T.G.I. Friday’s, Trek Bicycle Corp. and Woolworths Ltd.

But, as we previously reported, employees are growing increasingly unhappy at the company.

Earlier this month, Microsoft laid off 20 Yammer employees in sales and marketing. What really burned was that the company confirmed the layoffs to tech news outlet TechCrunch before management actually told employees about it.

For what it's worth, Yammer was on track to do $15-$30 million in sales in 2011, according to analysts. That would mean that 2012's revenue was $45-$90 million.